Summary of business and significant accounting policies - Deferred Costs (Details) $ in Thousands	3 Months Ended
	Sep. 30, 2020 USD ($)
Contract with Customer Asset [Roll Forward]
Balance, June 30, 2020	$ 80,669
Content licensing costs incurred	33,136
Customized software development costs incurred	695
Less: cost of revenue recognized	(38,459)
Balance, September 30, 2020	76,041
Content
Contract with Customer Asset [Roll Forward]
Balance, June 30, 2020	73,598
Content licensing costs incurred	33,136
Customized software development costs incurred	0
Less: cost of revenue recognized	(37,213)
Balance, September 30, 2020	69,521
Development
Contract with Customer Asset [Roll Forward]
Balance, June 30, 2020	7,071
Content licensing costs incurred	0
Customized software development costs incurred	695
Less: cost of revenue recognized	(1,246)
Balance, September 30, 2020	$ 6,520